Quantum Monte Carlo study of ground and first excited state of C,N, O,F, and Ne atoms using Slater-Jastrow-Backflow wave function |
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Authors: | Saeed Nasiri Mansour Zahedi |
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Institution: | Department of Chemistry, Faculty of Chemistry, Shahid Beheshti University, G.C., Tehran, Iran |
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Abstract: | All-electron fixed-node diffusion quantum Monte Carlo energies of the two lowest-lying states of C, N, O, F, and Ne atoms are reported. The Slater-Jastrow form is used as the trial wave function. We will use single- and multideterminant wave functions as the Slater part. The single-determinant wave function has been computed by the Hartree-Fock method and the multideterminant wave functions have been computed by the complete active space self-consistent field, configuration interaction with single and double excitation, configuration interaction with single, double, triple, and quadruple excitation and second-order configuration interaction. For the ground- and first excited states, the multideterminant wave functions have computed more than 99% of the correlation energy. Significant improvements have been achieved using the backflow transformations and up to 99.8% of the correlation energy has been recovered. A very good agreement with the experimental data has been obtained for the excitation energies. |
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Keywords: | backflow transformation excited state ground state of C N O an F atoms quantum monte-carlo Slater-Jastrow |
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